As camera-phones and personal digital assistances (PDAs) are being widely adopted in the marketplace, they become the ubiquitous platforms for visual search and mobile augmented reality applications. To support an application that requires image comparison, information either need to be uploaded from a mobile device to a server, or downloaded from the server to the mobile device. The amount of data to be transmitted and/or received over the wireless network becomes critical to the performance and ease-of-use of such applications.
Conventional feature-based retrieval systems typically employ a straightforward scheme for coding location information. In such systems, (x, y) coordinates of each feature are quantized to some fixed resolution, such as 8 bits per feature location. Then such quantized (x, y) pairs are stored and transmitted. For example, with an image having one thousand features and an 8-bit resolution is used, this scheme would require about 2K bytes of data per image. Such data coding scheme results in large amount of data need to be transmitted over the wireless network, which in turn adversely affects the performance and ease-of-use for visual search and mobile augmented reality applications.
Therefore, there is a need for systems and methods for coding feature location information that can address the above issues of conventional systems.